1. Field of the Invention
This invention relates to a packaged photocurable composition that includes a squeezable vial having a chamber that receives a quantity of photocurable material.
2. Description of the Related Art
Many liquid and semi-liquid compositions used in small quantities in the household, commercial or industrial applications are sold in small vials, such as dropper bottles, squeezable applicators and the like. Typically, such vials are relatively inexpensive and are disposed of once their contents have been exhausted or have not been used by a specified expiration date.
Many small vials used for containing and dispensing liquid and semi-liquid compositions are made of a flexible polymeric material. To dispense the composition, opposed wall portions of the vial are squeezed together by finger pressure to expel the composition through an outlet. The flexible wall portions are an advantage in that the user can control, to some degree, the amount and flow rate of the composition that is dispensed. In addition, flexible wall portions are less likely to break if the vial is unintentionally dropped or subjected to other kinds of abuse in comparison to vials made of glass or other rigid materials.
Squeezable polymeric vials have been long used for various medical and dental preparations. Examples include vials for eye and ear medications, suntan and sun screen compositions, body lotions, cosmetics, topical ointments and insect repellents. Commercial and industrial applications include compositions for film developing and other photographic applications, adhesives (such as cyanoacrylates), lubricants and the like.
Many squeezable vials are made of polymeric material that is sufficiently transparent or translucent so that the user may visually estimate the amount of a composition remaining in the vial. In some instances, the transparent or translucent material helps the user ascertain whether or not the composition has degraded. For example, the user may be able to determine whether or not an adhesive has unduly hardened or thickened by shaking the vial and observing the fluidity of the contents through the polymeric wall portions.
Some compositions that are contained in squeezable vials are curable upon exposure to light having wavelengths in the visible spectrum. Examples of photocurable compositions include certain dental (including orthodontic) adhesives and primers, dental luting cements and other dental preparations such as sealants and crown build-up material. In the past, vials containing such photocurable compositions have included a sufficient amount of pigment, such as carbon black, that absorbs light and blocks substantially all of the light from entering the chamber in the vial that would otherwise unduly cure the contained composition.
Unfortunately, opaque squeezable containers are not entirely satisfactory, since the user cannot visibly ascertain the amount of composition remaining in the vial or whether it has degraded. Some vials, and especially vials containing dental compositions, are relatively small and contain only a small amount of photocurable composition. With such vials, it is difficult to determine the amount of photocurable composition remaining therein by lifting the vial and estimating its weight, since the ratio of the weight of the vial to the weight of the composition is relatively large.